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s390/topology: correct topology mode proc handler

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Reuse proc_douintvec_minmax to simplify topology mode proc handler.
This also enforces correct range of 0-1 on proc writes and correctly
handles numbers starting with 0 or spaces.

Before:
$ echo 01 > /proc/sys/s390/topology
$ cat /proc/sys/s390/topology
0
$ echo ' 1' > /proc/sys/s390/topology
-bash: echo: write error: Invalid argument
$ echo 2 > /proc/sys/s390/topology
-bash: echo: write error: Invalid argument
$ echo 12 > /proc/sys/s390/topology
$ cat /proc/sys/s390/topology
1

After:
$ echo 01 > /proc/sys/s390/topology
$ cat /proc/sys/s390/topology
1
$ echo ' 1' > /proc/sys/s390/topology
$ cat /proc/sys/s390/topology
1
$ echo 2 > /proc/sys/s390/topology
-bash: echo: write error: Invalid argument
$ echo 12 > /proc/sys/s390/topology
-bash: echo: write error: Invalid argument
$ echo '   0' > /proc/sys/s390/topology
$ cat /proc/sys/s390/topology
0

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Vasily Gorbik 2018-06-24 12:28:46 +02:00 committed by Martin Schwidefsky
parent f149371e9e
commit 196851bed5
1 changed files with 18 additions and 25 deletions
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43
arch/s390/kernel/topology.c
View file

@ -579,40 +579,33 @@ early_param("topology", topology_setup);
static int topology_ctl_handler(struct ctl_table *ctl, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
unsigned int len;
int enabled = topology_is_enabled();
int new_mode;
char buf[2];
int zero = 0;
int one = 1;
int rc;
struct ctl_table ctl_entry = {
.procname = ctl->procname,
.data = &enabled,
.maxlen = sizeof(int),
.extra1 = &zero,
.extra2 = &one,
};
rc = proc_douintvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
if (rc < 0 || !write)
return rc;
if (!*lenp || *ppos) {
*lenp = 0;
return 0;
}
if (!write) {
memcpy(buf, topology_is_enabled() ? "1\n" : "0\n", ARRAY_SIZE(buf));
len = strnlen(buf, ARRAY_SIZE(buf));
if (len > *lenp)
len = *lenp;
if (copy_to_user(buffer, buf, len))
return -EFAULT;
goto out;
}
len = *lenp;
if (copy_from_user(buf, buffer, len > sizeof(buf) ? sizeof(buf) : len))
return -EFAULT;
if (buf[0] != '0' && buf[0] != '1')
return -EINVAL;
mutex_lock(&smp_cpu_state_mutex);
new_mode = topology_get_mode(buf[0] == '1');
new_mode = topology_get_mode(enabled);
if (topology_mode != new_mode) {
topology_mode = new_mode;
topology_schedule_update();
}
mutex_unlock(&smp_cpu_state_mutex);
topology_flush_work();
out:
*lenp = len;
*ppos += len;
return 0;
return rc;
}
static struct ctl_table topology_ctl_table[] = {